In recent years, demands are increasing on reduction in fuel consumption for a vehicle. A specific vehicle, such as a hybrid vehicle (HEV) and a vehicle employing an idling stop system, operates an engine less frequently, compared with a conventional vehicle. In addition, a specific vehicle currently employs a variable lift mechanism and an Atkinson cycle engine to reduce fuel consumption. Thus, as an engine is less frequently operated in a vehicle, or as a variable lift mechanism or an Atkinson cycle engine is increasingly employed in a vehicle, negative pressure in an intake manifold in such a vehicle is being remarkably reduced. A vehicle may be equipped with a vapor fuel processing apparatus configured to implement canister purge to supply evaporated fuel, which is produced in a fuel tank, through a canister into an internal combustion engine. As negative pressure in an intake manifold decreases, frequency of the canister purge and differential pressure for implementing the canister purge decreases. Therefore, it is increasingly becoming difficult to secure a quantity of gas needed in the canister purge. For example, a patent document 1 discloses a sealing valve for restricting outflow of evaporated fuel from a fuel tank.    [Patent Document 1] Publication of unexamined Japanese patent application No. 2004-156496
In such a configuration, as disclosed in the patent document 1, equipment of the sealing valve for restricting outflow of evaporated fuel from the fuel tank may cause increase in inner pressure of the fuel tank. In a condition, in which inner pressure of the fuel tank is high, a fill opening of the fuel tank may be opened. In such a case, evaporated fuel produced in the fuel tank may be emitted through the fill opening to the atmosphere. The patent document 1 further discloses a sensor, a switch, and/or the like equipped in a refueling lid or the fill opening to detect an operation for refueling. Further, when the operation for refueling is detected, the sealing valve is released. It is noted that, when the internal pressure of the fuel tank is high, it takes time to reduce the inner pressure of the fuel tank to a predetermined pressure, such as the atmospheric pressure, after the sealing valve is opened. The patent document 1 further discloses a configuration to prohibit an activity to open the fill opening, that is, not to permit refueling, in order to restrict emission of evaporated fuel through the fill opening, until release of the inner pressure of the fuel tank is completed.
It is further noted that, in the patent documents 1, a user may be kept waiting until the release of the inner pressure of the fuel tank is completed. Therefore, the system of the patent documents 1 may be inconvenient for a user hurrying in refueling.